Credentials include identification cards, driver's licenses, passports, and other documents. Such credentials are formed from credential or card substrates including paper substrates, plastic substrates, cards and other materials. Such credentials generally include printed information, such as a photo, account numbers, identification numbers, and other personal information. Credentials can also include data that is encoded in a smartcard chip, a magnetic stripe, or a barcode, for example.
Credential production devices process credential substrates by performing at least one processing step in forming a final credential product. One such process is a transfer or lamination process that transfers a material to a surface of the card substrate using a heated transfer roller of a transfer unit of the device. This process can be used to transfer an image to the surface of the card substrate and/or provide protection to the surface of the card substrate from abrasion and environmental conditions, for example.
Intermediate transfer films or transfer ribbons include a fracturable laminate or transfer layer, which is often referred to as a “thin film laminate,” that can be transferred to a surface of a card substrate using the heated transfer roller. Such transfer layers are generally continuous resinous materials that have been coated onto a continuous carrier layer or backing to form a transfer ribbon. The side of the resin material that is not attached to the continuous carrier layer is generally coated with a thermal adhesive which is used to create a bond between the resin and the surface of the substrate. The transfer roller is used to thermally activate the adhesive and press the resinous material against the surface of the substrate to bond the material to the surface. The carrier layer or backing is removed to complete the lamination process.
The transfer layer may also be in the form of a print intermediate, on which an image may be printed in a reverse-image printing process. In the reverse-image printing process, a print head is registered with a transfer section of the transfer layer, and an image is printed to the transfer section using the print head. Next, the imaged transfer section is registered with the card substrate and/or the transfer roller. The transfer roller is then used to activate the adhesive of the imaged transfer section causing the imaged transfer section to bond to the surface of the card substrate. The carrier layer or backing of the overlaminate material is then removed from the bonded imaged transfer section to complete the transfer of the image to the card substrate.
The transference of the transfer layer to the surface of a card substrate generally causes the card substrate to bend such that the surface that received the transfer layer becomes concave. This is generally due to the contraction of the surface and/or the transfer layer in response to cooling. One technique for handling such warpage of the card substrate, is to pass the substrate through a device that bends the card in a manner that overcomes the warpage, such as by temporarily forcing the surface of the substrate that received the transfer layer into a convex shape.